Means for regulation of dynamo-electric machines.



No. 782,340. PATENTED FEB. 14, 1905. A. S. HUBBARD.

MEANS FOR REGULATION OF DYNAMO ELECTRIC MACHINES.

APPLICATION FILED FEB. 20, 1902.

ZMZ/hasas [n 0012222 UNITED STATEs Patented February 1%, 1905.

PATENT QEE CE.

ALBERT S. HUBBARD, OF GREENVVICH, CONNECTICUT.

SPECIFICATION forming part of Letters Patent No. 782,840, dated February 14, 1905.

Application filed February 20, 1902. Serial No. 94,914.

To (LZZ whom/ it puny concern:

Be it known that I, ALBERT S. HUBBARD, a citizen of the United States, residing at Greenwich, in the county of Fairfield and State of Connecticut, have invented certain new and useful Improvements in Means for Regulation of Dynamo-Electric Machines, of which the following is a specification.

This invention relates to improvementsin means for regulation of dynamo-electric machines, and is applicable in connection with either generators or motors.

Sh Lint-Wound or compound-wound d ynamos and motors are more or less self-regulating as to maintenance of constant conditions of electromotive force or of speed, as the case may be, under varying loads; but in the case of circuits liable to sudden variations of load on account of connection with elevator, streetrailway, or other motors the voltage of the dynamo is liable to dip or the speed of a motor to slacken momentarily on sudden application of an abnormal load to the circuit, this momentary dip or slackening being due mainly to the sluggishness or self-induction of the field-magnet. The same momentary dip or lack of response may be due to the momentary slowing down of the driving-engine, due to sluggishness of the governor. My present invention is intended to prevent such momentary variation in voltage of the dynamo or speed of the motor, and the invention comprises an inductive device responding to sudden changes in the dynamo or motor circuit and influencing the field-magnet to overcome the corresponding sudden change in the voltage or speed. Said device preferably consists of a transformer having its primary included in the main circuit that is, in circuit with the armature of the dynamo or motorwhile the secondary is connected in series with the shunt field-coil or with a separate field-coil.

1n the accompanying drawings, Figure l is a diagram showing one embodiment of my invention, the secondary coil of the transformer being connected with a special field-coil of the dynamo or motor. Figs. 2, 3, and L are similar views showing other ways of connecting the induction devices according to my invention.

Referring to Fig. 1, the armature 1 of the dynamo-electric machine, generator, or motor is connected through the series field-coil 2 with the circuit-leads t, the shunt field-coil 3 being connected across said leads. The transformer or induction device has its primary coil 5 included in one side of the main circuit at, while the secondary coil of said transformer is connected in a circuit 7, including a special or separate field-coil 8, which is wound on the same cores as the usual series and shunt coils. l have indicated at 10 a variable load, such as a motor, and at 10 an equable load, such as electric lights. Under conditions of constant load this transformer and the supplen'ientary field-coil S are idle and without effect on the generator or motor; but in case of any sudden change in the load the transformer will respond and will send a current through the siu'iplementary field-coil that will tend to overcome momentarily the disturbing effect of this change on the circuit until the dynamo or motor has time to catch up or adjust itself to the new conditions. Thus in the case of a sudden increase of load on the circuit of a dynamo the effect of the corresponding increase of current in the main circuit will be to induce, through the transformer, a current in local circuit 7 in a direction to supplement the effect of the main magnetizing field-coils and tend to hold up the voltage generated by the dynamo and prevent any sudden drop. By this means the effect of any sudden variation in the powerload 10 is prevented from causing a momentary drop in potential, and the lights 10 are maintained at a steady illumination. \Vhen the main circuit ceases to increase, the inducing action will cease; but by that time the main series coil of the dynamo will have responded to the increase of current therein to maintain the proper condition of voltage, the object of the present invention being only to provide for the lack of instantaneousness of the ordinary regulating means d no to sluggishness either of the dynamo field-magnet or of the engine-governor. On a decrease of the main current a reverse action occurs, tending to prevent a momentary rise of potential. In case of a motor the eflect of a fall in potential on themain or supply circuit resulting, say, from a sudden increase of load at other points, as at motor 10, will be to cause the current through the motor to drop accordingly, and as this cur rentpasses through the primary ot' the trans- :t'ormer there will be induced in the secondary thereof a current that will traverse the supplementary tield-coil 6 and will temporarily diminish the excitation of the motor-field magnet until the change in potential ceases, by which time the main coil of the motor-field magnet will have had time to respond and by giving a relatively weaker tield allow the motor to hold up to normal speed under the lower electromotive lerce. Similarly for increase of electromotive Force the motorlield is strengthened momentarily by induction and then permanently by direct action of its series field.

Instead of providing a separate lield-coil for giving this temporary excitation .i may utilize the usual shunt lield-coil ot the dynamo for this purpose. Thus in Fig. 2 the secondary ot the transformer is connected in series with the field-coil 3 of a shunt-wound dynan'io, while the primary is connected directly in the main circuit. The transformer, as before, is without electromotive influence on the circuit until there is a change in current, when it causes by induction a temporary current to How through the shunt lield-coil, which tends to prevent any sudden change of voltage in the dynamo. In case of a connmnnd-wound dynamo the secondary of the transt'orn'ier would be included in circuit with the shunt lield-coil, while the primary would be in the main circuit either in series with the series field-coil, as shown in Fig. 3, or in shunt with said series coil, as in Fig. 4, being in either case responsive to changes in the main circuit. Of course it is evident that the eliect ot' the transformer can be regulated in any of the well-known ways 'for instance, varying the distance between the primary and secondary coils, vary ing the number of turns in the primary, or varying the number of turns in the secondary, or by means of shunts to the primary, or by means of opposing coils in the secomlary. Thus in Fig. 2 I have shown a switch 9 tor cutting out portions of the primary and in Fig. 3 an adjustable rheostatic switch 9 for shunting the primary.

In designing this system for use to aid the regulation of the dynamo the secondary primary should be so calculated as to compensate for the drop in voltage caused by the sluggishness of the iron and the momentary slowing up ot'the engine upon ap 'ilication of load, also for the momentary distortion of field consequently produced.

My invention is also applicable to systems of distribution comprising a storage battery and booster, and the same is shown and described in my application for Letters Patent, Serial No. 166,582, liled July 22, 1903.

Having thus described my invention, the

vsaseo following is what I'claim as new therein and desire to secure by Letters Patent:

1. The combination with a dynamo-electric machine, the iield of which is responsive to electrical changes in its external circuit, of induction means responsive only to variations in load in said circuit and influencing the field of said machine to stin'iulate or quicken its responsive action.

2. The combination with a dynamo-electric machinehavinga self-regulatinglield-wimling and awork-circuit connected with said dynamo, of an induction device having primary and secondary members responsive to a state 01 change in electrical conditions in the said workcircuit to control the dyilame-electric machine during such state oi change in such manner as to temporarily counteract the effect of such changing condition on the dynamo-electric machine.

The combination with a dynamo-electric machinehavingaself-regulatingfield-winding and a wmk-circuit col'mected with said dynamo, of an induction device having primary and secomlary members connected to a field-magnet coil of said dynamo-electric machine and responsive to a condition of changingcurrent in said circuit to control the excitation of the held-magnet ot' the dynamo-electric machine so as to temporarily counteract the el'lect of such changing condition on the eleetromotive force of the dynamo.

L. The combination with a dynamo-electric machine having a self-exciting field-winding responsive to electrical conditions in its external circuit, of an induction device responsive to changes in the external circuit o't said machine, said induction device connected with a field-winding of said machine and individually influencing said lield to stimulate or quicken the responsive action thereof.

The combination with a dynamo-electric machine having a self-exciting lield-winding responsive to electrical conditions in the external circuit, said held-winding comprising a shunt-coil, ol an induction device responsive only to variations in load in the external circuit and connected with the shunt field-coil ot the dynamo-electric machine to stimulate its action.

(5. The combination with a dynalno-electric machine having a self-regulating field-winding responsive to electrical conditions in its external circuit, of a translorl'ner having its primary connected with said circuit and responsive only to variations in load therein and its secondary COHDGCtOtl to a lield-wimlingoi said machine to stimulate or quicken the responsive action thereot'.

7. The combination with a dynamo-electric machine havii'ig a shunt field-winding, ol a transformer having its primary connected in the external circuit ol said machine responsive only to variations in load therein, and having its secondary connected with the said.

shunt field-Winding to stimulate the responsive action thereof.

8. The combination With a dynamo-electric machine, having a compound field-Winding and means to stimulate or quicken the responsive action of said field, said means comprising a transformer having its primary in the external circuit of said machine and responsive only to variations in load therein and its secondary connected With the shunt-Winding of said machine.

9. The combination With a dynamo-electric machine having its field responsim to electrical changes in the external circuit, of additional means to influence the responsive action of said field, said additional means comprising a transformer having its primary conformer consisting of a switch for cutting in I or out portions of one of its coils.

ALBERT S. HUBBARD. \Vitnesses:

An'rnnn P. KNIG 1 rr,

J. GREEN. 

